One popular method of fishing for cod from boat is uptide boatcasting, which was originally designed for areas where the sea was fairly shallow. Here both the shadow of the boat and the slap of the water against the hull set up a series of vibrations that put the fish off, creating, in effect, a scare zone.
When you do cast from a boat you should bear firmly in mind that this is potentially very dangerous. The uptide boatcasters designed for this method are quite capable of hurling a heavy lead out to sea with considerable force so you do, really, need to be careful. All you should do is a straight overhead thump, nothing fancy, just enough to send the bait away far enough from the scare zone to put you in amongst the fish.
As far as reels go, multipliers, preferably those with a ratchet, are ideal for this type of fishing. Personally I like to use my trusty old ABU Ambassador 7000 which, although showing its age, is still going well after more than a quarter of a century’s use.
In shallow water, a 'scare zone' is created by both the shadow of the hull and the sound of the water slapping against its side. Fish beyond this area and the chances are that your catches will increase.
Anglers able to place their baits beyond this scare zone caught more and better fish since this was where the fish were congregated in greater numbers. Far fewer fish entered the scare zone and so this gave them the edge over conventional downtide trotting. Tackle was also fairly simple, basically just a running leger with a tail end breakaway or similar weight suspended from a link. When the angler cast he or she just draped their bait from one of the trailing wires, stepped to the other side of the boat, so that the tip of the rod was over the water and not in danger of catching some unfortunate soul in the seat of his pants, and cast. When the tackle hit the water it was allowed to sink, all the while giving out more line to allow the angler to create a bow between the rod tip and the spiked lead on the ocean floor. The rod is then placed on the deck and the tip of the rod watched carefully for signs of a bite, which will, most probably, spring the lead loose from its grip in the process.
Although uptide boatcasting is a very effective means of catching fish it is also very much dependant on the depth of water in which you are fishing. Personally I would only use it in less than forty feet of water. In deeper water the old fashioned drop your tackle down and let it ‘go with the flow’, so to speak, is just as effective, especially where you marry it up with a long, flowing trace.